Grazing Management Strategies for Reseeded Rangelands in the East Kimberley Region of Western Australia.

1991 ◽  
Vol 13 (1) ◽  
pp. 14 ◽  
Author(s):  
RB Hacker ◽  
SB Tunbridge
Keyword(s):  
Management System ◽  
Management Strategies ◽  
Dry Season ◽  
Perennial Grasses ◽  
Grazing Management ◽  
Research Station ◽  
Stocking Rate ◽  
Perennial Species ◽  
Wet Season ◽  
Continuous Grazing

Grazing management strategies involving continuous grazing, wet season rest, dry season rest and a range of stocking rates of steers were evaluated on reseeded rangeland at Ord Regeneration Research Station by the use of temporary exclosures within continuously grazed paddocks. The rangeland is a patchwork of plant communities in various stages of regeneration. Under continuous grazing, liveweight gain in three of the four years of the trial was more closely related to botanical differences between paddocks than to stocking rate although all paddocks were confined to the one land unit. Animals generally selected those parts of the pasture where regeneration of perennial grasses was least advanced and the vegetation was characterized by short annual and semi-perennial species. Differences in the yield of these species between paddocks accounted for much of the variation in liveweight gain. Perennial species contributed most to animal production when seasonal conditions were poor. Over the study as a whole, year-in-year-out stocking rate was much more important than management system (proportion of wet season grazing) in determining vegetation changes. Nevertheless, selective grazing of the short grass patches will prevent the use of a continuous grazing strategy in these pastures. However, continued regeneration should be feasible under a tactical management system in which grazing is managed to ensure that a minimum level of cover is maintained on the short grass phase and that the end of dry season utilization level for the key perennial species does not exceed an average (over years) of about 30 per cent.

The inter-relationships of grazing method and stocking rate in the efficiency of pasture utilization by dairy cattle

1963 ◽  
Vol 61 (2) ◽  
pp. 147-166 ◽  
Author(s):  
C. P. McMeekan ◽  
M. J. Walshe
Keyword(s):  
Dairy Cows ◽  
Large Scale ◽  
Age Distribution ◽  
Grazing Management ◽  
Vanishing Point ◽  
Stocking Rate ◽  
Rotational Grazing ◽  
Continuous Grazing ◽  
Grazing System ◽  
Stocking Rates

1. A large-scale grazing management study comparing rotational grazing and continuous grazing with dairy cows at two stocking rates over four complete production seasons is described.2. The four treatments were: (i) controlled grazing, light stocking rate; (ii) controlled grazing, heavy stocking rate; (iii) uncontrolled grazing, light stocking rate; (iv) uncontrolled grazing, heavy stocking rate.Each treatment involved 40 cows for a first 2-year phase and 42 cows for the following 2 years. Each herd had a normal age distribution pattern and seven 2-year-old first lactation heifers (17% of total herd) were introduced each year to maintain this pattern.3. Stocking rate was the more important factor affecting the efficiency of pasture utilization as measured by per acre output of milk and butterfat. In general, high stocking was associated with higher outputs per acre despite lower yields per animal.4. Grazing method was of less importance. In general, controlled rotational grazing was superior to uncontrolled continuous grazing, both per animal and per acre, but the average influence even of these extremes of management was only half that of stocking rate.5. Significant interactions between stocking rate and grazing method existed. Under continuous grazing a point was reached where production per acre declined to the vanishing point with increased stocking rate due to excessive depression of per cow yield: this point was not reached under rotational grazing at the same high stocking levels.6. The results suggest that optimum stocking rate under rotational grazing occurs at a level some 5–10% higher than under continuous grazing. A depression of 10–12% in per cow yield, compared with more lenient grazing, corresponds with optimum stocking level irrespective of the grazing system. This estimate is suggested as a guide line in applying the principles involved.

Bio-economic evaluation of grazing-management options for beef cattle enterprises during drought episodes in semiarid grasslands of northern Australia

2021 ◽  
Vol 61 (1) ◽  
pp. 72
Author(s):  
M. K. Bowen ◽  
F. Chudleigh ◽  
D. Phelps
Keyword(s):  
Beef Cattle ◽  
Management Strategies ◽  
Grazing Management ◽  
Economic Modelling ◽  
Stocking Rate ◽  
Northern Australia ◽  
Management Scenarios ◽  
Management Options ◽  
Herd Management ◽  
Stocking Rates

Context The large inter-annual and decadal rainfall variability that occurs in northern Australian rangelands poses major challenges for the profitable and sustainable management of grazing businesses. Aims An integrated bio-economic modelling framework (GRASP integrated with Breedcow and Dynama (BCD)) was developed to assess the effect of alternative grazing-management options on the profitability and sustainability of a beef cattle enterprise in the central-western Mitchell grasslands of Queensland over a multi-decadal time period. Methods Four grazing-management strategies were simulated over a 36-year period (1982–2017) in the GRASP pasture-growth model, using historic climate records for Longreach in central-western Queensland. Simulated annual stocking rates and steer liveweight-gain predictions from GRASP were integrated with published functions for mortality and conception rates in beef-breeding cattle in northern Australia, and then used to develop dynamic BCD cattle-herd models and discounted cash-flow budgets over the last 30 years of the period (1988–2017), following a 6-year model-equilibration period. The grazing-management strategies differed in the extent to which stocking rates were adjusted each year, from a common starting point in Year 1, in response to changes in the amount of forage available at the end of the summer growing season (May). They ranged from a low flexibility of ‘Safe stocking rate’ (SSR) and ‘Retain core herd’ (RCH) strategies, to a moderate flexibility of ‘Drought responsive’ (DR), to a ‘Fully flexible’ (FF) strategy. The RCH strategy included the following two herd-management scenarios: (1) ‘Retain herd structure’, where a mix of cattle were sold in response to low pasture availability, and (2) ‘Retain core breeders’, where steers were sold before reducing the breeder herd. Herd-management scenarios within the DR and FF strategies examined five and four options respectively, to rebuild cattle numbers and utilise available pasture following herd reductions made in response to drought. Key results Property-level investment returns expressed as the internal rate of return (IRR) were poor for SSR (–0.09%) and the three other strategies when the herd was rebuilt following drought through natural increase alone (RCH, –0.27%; DR, –1.57%; and FF, –4.44%). However, positive IRR were achieved when the DR herd was rebuilt through purchasing a mix of cattle (1.70%), purchasing pregnant cows (1.45%), trading steers (0.50%) or accepting cattle on agistment (0.19%). A positive IRR of 0.70% was also achieved for the FF property when purchasing a mix of cattle to rebuild numbers. However, negative returns were obtained when either trading steers (–2.60%) or agistment (–0.11%) scenarios were applied to the FF property. Strategies that were either inflexible or highly flexible increased the risk of financial losses and business failure. Property-level pasture condition (expressed as the percentage of perennial grasses; %P) was initially 69%P and was maintained under the DR strategy (68%P; average of final 5 years). The SSR strategy increased pasture condition by 25% to 86%P, while the RCH and FF strategies decreased pasture condition by 29% (49%P) and 65% (24%P) respectively. Conclusions In a highly variable and unpredictable climate, managing stocking rates with a moderate degree of flexibility in response to pasture availability (DR) was the most profitable approach and also maintained pasture condition. However, it was essential to economic viability that the property was re-stocked as soon as possible, in line with pasture availability, once good seasonal conditions returned. Implications This bio-economic modelling analysis refines current grazing-management recommendations by providing insights into both the economic and sustainability consequences of stocking-rate flexibility in response to fluctuating pasture supply. Caution should be exercised in recommending either overly conservative safe stocking strategies that are inflexible, or overly flexible stocking strategies, due to the increased risk of very poor outcomes.

Levels of total nitrogen and total volatile fatty acids in the rumen fluid of sheep under different grazing management systems

1967 ◽  
Vol 7 (28) ◽  
pp. 434
Author(s):  
WR McManus
Keyword(s):  
Fatty Acids ◽  
Total Nitrogen ◽  
Volatile Fatty Acids ◽  
Rumen Fluid ◽  
Subterranean Clover ◽  
Grazing Management ◽  
Stocking Rate ◽  
Continuous Grazing ◽  
Grazing System ◽  
Stocking Rates

Concentrations of total nitrogen and total volatile fatty acids in the rumen fluid of sheep grazing improved pastures were measured for ten months in a dry year on the southern tablelands of New South Wales, and the concentrations of nitrogen and volatile fatty acids (V.F.A.) were related to season, wool production, and grazing management. The observations were made during two long-term grazing management experiments. In the first experiment four groups of breeding Merino ewes grazed a Wimmera ryegrass-subterranean clover (Lolium rigidum Gaud.-Trifolium subterraneum L.) pasture. A deferred grazing system (autumn saving) of pasture management was compared with continuous grazing at stocking rate treatments equivalent to 7.0 and 3.5 ewes to the acre. In the second experiment two groups of Merino weaners grazed a Phalaris tuberosa-subterranean clover pasture at a stocking rate equivalent to 8.6 sheep to the acre. One group received a hay supplement, the other did not. In both experiments nitrogen values were low between late autumn and mid-winter and again between late spring and summer, and high in early autumn and again in spring (P<0.05). The low levels were about 55 per cent of peak autumn and spring levels in (experiment 1) and 60 per cent of peak autumn and spring levels in (experiment 2). Total V.F.A. did not vary significantly between seasons in either experiment. At the higher stocking rate the ewes had lower levels of rumen total nitrogen than at the lower stocking rate. V.F.A. did not vary consistently between stocking rates. At both stocking rates ewes on the autumn saving system of grazing management had more nitrogen in the rumen fluid during late pregnancy and early lactation than did those on the continuous grazing system (P<0.001). After the ewes had access to the saved pasture, autumn saving resulted in a higher concentration of volatile fatty acids than continuous grazing (P< 0.05). Although feeding a hay supplement benefited the weaners the concentrations of total nitrogen in the rumen fluid of the two groups of sheep were similar. There was a fairly consistent tendency for the group receiving hay to have lower concentrations of volatile fatty acids in their rumen fluid. Possible reasons for these effects are discussed.

Nitrogen contributed by grain legumes to rice grown in rotation on the Cununurra soils of the Ord Irrigation Area, Western Australia

1987 ◽  
Vol 27 (1) ◽  
pp. 155 ◽  
Author(s):  
AL Chapman ◽  
RJK Myers
Keyword(s):  
Green Manure ◽  
N Uptake ◽  
Dry Season ◽  
Green Gram ◽  
Research Station ◽  
Rice Grain ◽  
Wet Season ◽  
Sesbania Cannabina ◽  
Irrigation Area ◽  
Bare Fallow

The uptake of nitrogen (N) by dry season rice following wet season crops of soybean (for grain or green manure), green gram, Sesbania cannabina (a native legume), a cereal (sorghum or dryland rice for grain), or bare fallow, was studied for 3 cropping cycles over 4 years. The work was done on Cununurra clay (0.04% N) at Kimberley Research Station near Kununurra, W.A., in the Ord Irrigation Area. Stubbles were returned to the soil except in the first cycle when (excluding the green manure treatment) all tops were removed from the plots at maturity. There was a 12-month bare fallow period between the first and second cycles. Dry season rice was drill-sown with or without 100 kg ha-1 of N applied as urea at permanent flooding. Soybean, green gram and Sesbania crops accumulated 290-360, 80-130 and 110-180 kg N ha-1, respectively, in the tops at maturity. An average of about 40 kg N ha-1 was present in the stem bases and roots (0-20 cm depth). Estimates of nitrogen fixation based on 15N dilution measurements ranged from 65-72% of total plant N when the legumes were grown after 12 months fallow, to 93-95% when they were grown immediately following dry season rice. Fertiliser N at 25 kg ha-1 applied presowing ('starter' N) had no significant effect on legume N yield at maturity. N returned in leaves, stems and hulls averaged 30, 50 and 80 kg N ha-1 for green gram, soybean and Sesbania, respectively. Rice grain yields and N uptake at maturity were generally highest after Sesbania and lowest after a wet season cereal crop. Differences among treatments were small and related to the quantity of N returned in residues. On average, 11% of the N in the residues was recovered in the tops of the following rice crop. Rice yields increased over the 4-year period, but mean increases were similar for legume and non-legume treatments. The average apparent recovery of N applied as urea to dry season rice at permanent flooding was 76%. The inclusion of a soybean cash crop in the rotation offers the possibility of a marginal reduction in the need for N fertiliser.

Effects of grazing management on botanical composition of native grass-based pastures in temperate south-east Australia

2000 ◽  
Vol 40 (2) ◽  
pp. 225 ◽  
Author(s):  
D. L. Garden ◽  
G. M. Lodge ◽  
D. A. Friend ◽  
P. M. Dowling ◽  
B. A. Orchard
Keyword(s):  
Management Strategies ◽  
Grazing Pressure ◽  
Grazing Management ◽  
Botanical Composition ◽  
Holcus Lanatus ◽  
Themeda Triandra ◽  
Continuous Grazing ◽  
Wide Range ◽  
Drought Conditions ◽  
Native Pastures

Grazing management strategies to alter botanical composition of native pastures were investigated at 4 locations in the high rainfall zone of south-east Australia, including Tasmania. These studies were conducted as part of the Temperate Pasture Sustainability Key Program, which evaluated the effects of grazing management on a wide range of pasture types between 1993 and 1996. Pastures in this study were based on Aristida ramosa/Bothriochloa macra, Microlaena stipoides–Austrodanthonia spp. or Themeda triandra–Austrodanthonia spp. Seasonal rests, increased grazing pressure in spring, mob stocking and cutting for hay were compared to continuous grazing at all sites. In addition, specific local treatments were tested at individual sites. Changes in composition resulting from the treatments were minimal at most sites. This may have been due to a combination of the inherent stability of the pastures, the relatively short duration of the experiments, and the drought conditions experienced, which minimised differences between treatments. Some strategies to alter composition of natural pastures are suggested. In the Aristida–Bothriochloa pasture there was a general decrease in Aristida and an increase in Bothriochloa, which was largely unaffected by the type of grazing management applied. The combination of drought conditions and increasing grazing pressure was sufficient to alter composition without specific management strategies being necessary. In the Themeda–Austrodanthonia pasture, resting in spring, 12-month rests or cutting for hay (which involved a spring rest) allowed Themeda to increase in the pasture. The Microlaena–Austrodanthonia pastures were very stable, especially where annual grass content was low. However, certain treatments allowed Microlaena to increase, a result which is regarded as being favourable. The major effects in these latter pastures were on undesirable species. Vulpia spp. were reduced by resting in autumn and increased spring grazing pressure, while Holcus lanatus was increased dramatically by resting in spring and was also increased by resting in autumn or winter, but only when conditions were suitable for growth of this species. In many cases, treatment differences were only expressed following recovery from drought, showing that timing of grazing management to achieve change is critical.

Chemical weed control in the Ord River Valley. 3. Cotton

1964 ◽  
Vol 4 (15) ◽  
pp. 321
Author(s):  
Rijn PJ van
Keyword(s):  
Weed Control ◽  
Active Ingredient ◽  
Dry Season ◽  
River Valley ◽  
Research Station ◽  
Wet Season ◽  
Residual Action

Between 1960 and 1963, four preliminary experiments on herbicides for cotton were carried out at Kimberley Research Station. Diuron, applied pre-emergence at rates of 1/2-1 lb an acre active ingredient (a. i.), and dicryl, applied seven to ten days after emergence at rates of 3-6 lb an acre a. i., gave satisfactory weed control. Diuron, because of its longer residual action (six weeks in early wet season, two months or more in late wet and early dry season) is preferred, and is recommended as the standard herbicidal treatment for Ord River cotton crops.

Evaluation of management options for increasing the productivity of tropical savanna pastures. 3. Trees

1989 ◽  
Vol 29 (5) ◽  
pp. 631 ◽  
Author(s):  
WH Winter ◽  
JJ Mott ◽  
RW McLean
Keyword(s):  
Dry Season ◽  
Perennial Grasses ◽  
Fertility Level ◽  
Wet Season ◽  
Management Options ◽  
Themeda Triandra ◽  
Weight Losses ◽  
Nitrogen Concentrations ◽  
The Mean ◽  
Stocking Rates

The effect of killing trees upon the production and quality of native perennial grasses, Themeda triandra, Chrysopogon fallax, Sehima nervosum, and Sorghum plumosum, and oversown legumes from the genus Stylosanthes, was studied over 4 years at Katherine, in the semi-arid tropics of northwestern Australia. The pastures were either unfertilised or received low inputs of superphosphate, and for each fertility level were grazed at 3 stocking rates. At no time were legume yields affected by killing the trees but, in the first 3 years, the amount of grass was approximately twice as much when the trees were killed. During this period the mean grass yields declined 4-5 fold from about 2.2 t/ha. By the fourth year the advantage from tree killing upon grass yield was apparent only at the lowest stocking rates at each fertility level. Nitrogen concentrations of the grasses and legumes, with the exception of S. hamata, were increased 7 and 10% respectively above the mean annual values of 0.89 and 1.75% where the trees were killed, while the phosphorus and sulfur concentrations were not affected. Tree killing had no effect upon wet season liveweight gains during the last 2 years of the experiment. However, there were some benefits during the dry season when weight losses were lower for most treatments during the early dry season (June-September) and also lower for the lowest stocking rate treatment without fertiliser during the late dry season (October-November).

scholarly journals The effect of different pasture management strategies in north-west Queensland on liveweight gain and wool growth rate of several groups of young sheep.

1985 ◽  
Vol 7 (2) ◽  
pp. 75 ◽  
Author(s):  
RGA Stephenson ◽  
DA Pritchard ◽  
PM Pepper ◽  
PT Connelly
Keyword(s):  
Growth Rate ◽  
Dry Matter ◽  
Management Strategies ◽  
Live Weight ◽  
Dry Season ◽  
Wet Season ◽  
Pasture Management ◽  
North West ◽  
Wool Growth ◽  
Significant Difference

The effect of three different pasture management strategies on liveweight gain and wool growth rate of young(weaner) sheep was examined immediately after weaning on Mitchell grass-Flinders grass pastures during the dry season of north-west Queensland. The pasture management strategies were designed to mimic various industry situations, while the performance of four different progeny groups was compared and used to provide an overall assessment of pasture quality. Pasture treatments (experiment 1) consisted of three paddocks, a harvested (c. 8% of pasture harvested and baled) and spelled, a spelled, and a continuously grazed paddock. Spelled paddocks were not grazed during and after the wet season for a period of six months while the continuously grazed paddock was continuously stocked before the experiment. Experiment 2 consisted of spelled and continuously grazed paddocks. Pastures were evaluated by measuring the changes in composition and quality (experiment 1) and the responses in liveweight gain (experiments 1 and 2) and wool growth of the weaners (experiment 1). Marked improvements (c. 100%) in weaner growth rates occurred in the spelled paddocks. Greasy wool production by three groups of ewes in experiment I was about 14% greater in the harvested paddock than in the others. At the start of the trial there were no significant differences in dry matter yield but a significant difference in botanical composition occurred between paddocks. The changes in dry matter that occurred between the beginning and end of grazing were not significantly different between paddocks. Before gazing, forbs made up approximately 16%, 4% and 1% of pastures in harvested, spelled and continuously grazed paddocks respectively. The change in the percentage forbs that occurred between the beginning and end of the grazing period was significantly greater in the harvested paddock than in the other paddocks indicating preferential selection and intake by sheep. The differences in weaner live weight and wool growth between paddocks suggest that paddock management can improve weaner productivity. The study also indicates that paddock management could be successfully used to increase the percentage of forbs and quality of the pasture during the dry season. The superior wool growth of two progeny groups also suggests that improved productivity of breeding flocks in the tropics is possible if superior sheep can be identified. The results highlight the importance of preferential management of pasture for weaners so that productivity advantages can be exploited.

scholarly journals SUPERVIVENCIA DE PROPÁGULOS DE RHIZOPHORA MANGLE BAJO TENSORES AMBIENTALES EN EL BRAZO CALANCALA DEL RÍO RANCHERÍA, CARIBE COLOMBIANO

2016 ◽  
Vol 45 (2) ◽  
Author(s):  
Ostin Garcés Ordoñez ◽  
Martha Ligia Castellanos Martínez
Keyword(s):  
Rhizophora Mangle ◽  
Dry Season ◽  
The Sun ◽  
Wet Season ◽  
Direct Exposure ◽  
Continuous Grazing ◽  
Environmentally Responsible ◽  
Del Rio ◽  
And Control ◽  
Experimental Plots

The survival of Rhizophora mangle propagules was assessed by direct seeding in the presence and absence of stressful factors (grazing of goats) and limitations factors of mangroves (hydric deficit and sunshine) in the Calancala branch of the Ranchería River, La Guajira, Colombia, assuming as hydric deficit the dry season, and sunshine the direct exposure to the sun. Four experimental plots of 100 m2 were established, located in different sunshine conditions, two under tree shade and two exposed to the sun. Some plots were enclosed in order to protect propagules from grazing, and others were exposed to grazing. Significant differences in propagules survival was found between conditions of hydric deficit (dry season) and availability of water (wet season) (χ² log-rank; p<0.05). In dry season the propagules did not survive because the low water availability and high sunshine. During rainy season, survival was greater in absence of goats grazing (0.46-0.96), in comparison with those exposed to goats grazing (0.0), because they ate propagules. In conclusion, survival of R. mangle propagules is affected by limitations factors and continuous grazing goats, this stressful factor required surveillance and control in order to mitigate damage to mangroves, and lead to environmentally responsible livestock practices.

scholarly journals Livestock weights in response to three whole-farmlet management systems

2013 ◽  
Vol 53 (8) ◽  
pp. 727 ◽  
Author(s):  
G. N. Hinch ◽  
J. Hoad ◽  
M. Lollback ◽  
S. Hatcher ◽  
R. Marchant ◽  
...  
Keyword(s):  
Soil Fertility ◽  
Management Strategies ◽  
Experimental Period ◽  
Supplementary Feeding ◽  
Grazing Management ◽  
Stocking Rate ◽  
Rotational Grazing ◽  
Average Value ◽  
Management Regime ◽  
Similar Range

This paper reports changes in livestock weights recorded in a whole-farmlet experiment, which aimed to examine the profitability and sustainability of three different pasture and grazing management strategies. The assessment of liveweights was considered a key component of measuring the integrated effects of the farmlet-scale treatments. The three farmlets comprised a typical management regime, which employed flexible rotational grazing over eight paddocks with moderate soil fertility (farmlet B), a system based on the same grazing management and paddock number but with higher levels of sown pasture and soil fertility (farmlet A) and a farmlet with moderate soil fertility and intensive rotational grazing over 37 paddocks (farmlet C). Early in the experimental period, there were no significant differences between farmlets in the liveweight of any class of livestock. However, from the second year onwards, as the pasture renovation, soil fertility and grazing management treatments took effect, differences in liveweight between farmlets became more apparent and significant. The stocking rate, which was treated as an emergent property of each farmlet, reached a maximum annual average value after 5 years of 12.6, 8.5 and 7.7 dry sheep equivalents (dse)/ha on farmlets A, B and C representing 84, 113 and 51% of their respective target stocking rates which were 15, 7.5 and 15 dse/ha. The liveweights of ewes, both before joining and during pregnancy, varied with year and farmlet with those on farmlets A and B tending to be significantly heavier than those on farmlet C. From 2003 to 2006, liveweights were significantly (P < 0.001) affected by a wide array of factors and their interactions including: date, ewe age, green digestible herbage, legume herbage mass, proportion of farmlet grazed, stocking rate and level of supplementary feeding. The weights of lambs/weaners/hoggets, both pre- and post-weaning, were at times also higher on farmlets A and B compared with those on farmlet C and were affected by a similar range of factors to those which affected ewe weights. Similar relative differences also applied to the liveweights of the other livestock run on the farmlets, namely wethers and non-reproductive cattle. The results suggest that stocking rate was able to be increased towards the higher target of farmlet A due to the higher level of pasture renovation and soil fertility on that farmlet, which led to high liveweights per head as well as the higher stocking rate. However, as the stocking rate increased on farmlet A, the differences between farmlets in liveweight per head diminished and the need for supplementary feeding increased. In contrast, the intensive rotational grazing practised on farmlet C did not allow the farmlet to increase its stocking rate towards its higher target. It appears that the higher proportion of each of farmlets A and B grazed at any one time allowed all classes of livestock to reach higher liveweights per head than on farmlet C, due presumably to the greater proportion of those two farmlets grazed at any one time.

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